Trino Prometheus connector is converting all the metric names from Prometheus into Lowercase and hence, queries to prometheus are failing

[nikitag55]

I'm using Trino Prometheus Connector. Prometheus allows metrics names following regex pattern:

[a-zA-Z_:][a-zA-Z0-9_:]*.

which means that metric names with upper case letters are also allowed.

Now, I have some of the metrics with name like:

Client_mount_disk_cache_hit_requests_total

When I use Trino Prometheus connector and do a query like:

cur.execute("""SHOW TABLES""")

It outputs table name as client_mount_disk_cache_hit_requests_total instead of Client_mount_disk_cache_hit_requests_total i.e it converted it into lowercase.

Now, when I'm trying to query Client_mount_disk_cache_hit_requests_total metric/table further in Trino using:

cur.execute("""SELECT * FROM Client_mount_disk_cache_hit_requests_total""")

or

cur.execute("""SELECT * FROM client_mount_disk_cache_hit_requests_total""")

It throws error like:

"prometheus.default. client_mount_disk_cache_hit_requests_total' does not exist"

because Prometheus contains the metric as: Client_mount_disk_cache_hit_requests_total and not client_mount_disk_cache_hit_requests_total and Prometheus is case sensitive with metric names.

Trino is converting everything into Lowercase and hence, metrics are not queryable in Prometheus.

[ebyhr]

Relates to #17. Some connectors have case-insensitive matching config, but Prometheus connector doesn't.